9s on a budget.

[Charlie @ Evergreen]

If you think its the pump LPH yours is 160 and the Walbro 392 is 255 lph we use on 400 plus hp car engines same size fitment.

[johnb]

Hello to all,

Ok it's that time of year again.
Drag strip opens next month.

Got a question for the turbo guru's.

I'm happy with the spring in my Wastegate, gives me a nice controlled max 23 psi.

Not keen to install a softer spring and use a reference bleed off device, they are just shit, had no success adjusting the little bastard's.

So can I induce a controlled leak to give better launches?

Needle valve, plus 12 volt solenoid with a timer,
So leaving the line turbo can't build max boost due to the big leak, adjustable with needle valve.
Set timer or (push a button) to give enough time to select second-third gear, solenoid valve closes giving full boost.

Obviously doesn't work, but why?
When I had boost leaking from the inlet rubbers my 60 foot time seems better, far less wheelies.
Anyway just a thought.

Cheers JB

[Lorcan]

The default position of the wastegate is shut. The turbo will build boost (on WOT) unti manifold pressure exceeds spring pressure, then the wastegate opens, relieving exhaust pressure and slowing the turbo.

If you fit a leak in the wastegate hose the wastegate will still stay shut until it sees manifold pressure equal to spring pressure. Bleeds, needle valves and solenoids are all ways of increasing boost above spring pressure by delaying this effect. You should fit a lighter spring and use some kind of boost controller.

[johnb]

Hi Lorcan,

Yep, that I understand, but I'm not interfering with the wastegate signal at all.
I'm thinking of relieving boost pressure between the Intercooler and throttle bodies, where my Bov used to reside.Launch at 10 psi and progressively increase boost with a timer and solenoid valve.
I see some large diesel cars dump the boost to save the transmission on launch,kind of along that line, I'll draw a picture and post, see what you recon. 

[Charlie @ Evergreen]

Might have to run a progressive electronic boost controller that will launch with a lower setting and hits higher setting with electronic controller set to your parameters? Not sure you can do that manually.

[Würstchens-Turbo 810]

Might have to run a progressive electronic boost controller that will launch with a lower setting and hits higher setting with electronic controller set to your parameters? Not sure you can do that manually.

Hi , can you post a link to this controller for an example
and it works with a PCIIIusb ?

[johnb]

Hi all 
About time I added.

Ive had some real issues with the bike misfiring above 4000 Rpm,
Symptoms had me looking at spark, so new plugs, changed coils, checked voltage at coils, even ran a power supply direct from the battery, but same issue, bike rides linear until boost develops and then stops as if kill switch activated. Continued on with engine temp sensor, testing and replacing earth connections but no change. Only recently replaced the inline fuel filter so didn't expect issues with the fuel system, but that was the cause.
The race fuel I added the previous meeting caused the tank liner to break down and block the petcock.

So the tank wrapped in a couple of old blankets with chain, nuts, bolts etc within and into the cement mixer for a few hours, the tank now clean with no old liner installed back on the bike, I checked the fuel flow rate through the inline filter into a container and appeared to pump well.
Start her up, fuel pressure good at idle, 36 psi, go for a ride, exact same issue, WTF, pulled injectors removed microsieves etc all clean, only when I blew both ways through the inline filter did I find the filter was blocked, seems the race fuel had detached the filter element within allowing the filter medium to move and block the outlet side of the filter, but only at high flow???

So off to the strip yesterday, First run 10.7 Sec @ 15 psi, obvious air leak as the wastegate is set at 22 psi.

Leak found @ the intercooler clamp, 
Next run started with a big wheelstand which caused me to panic and touch the rear brake to lower the front, back on the throttle and ran 10.97 sec, but @ 142.14 MPh which is pretty impressive for the old shitter.

Couple more runs all improving.
Last run 10.2 sec @ 136 Mph.
Last run was going well until last 100 meters, sounded like the clutch slipping, at the same time slight headshake, I had to shut down and coast across the line, does this sound correct? Until now bike has been super smooth? Still happy with a 10.2.
Anyway enough dribble.

So the moral of this story, if you dont know what your doing, ( Me) DONT use fucking race fuel, aggressive bastard of a stuff that slowed my bike and cause many hours of head scratching. 

Ps I'm back on 98 octane where I'll stay.
Couple of timing slips for your viewing pleasure,

Cheers JB

[Georgeturbo]

Looks like your getting things sorted and starting to put some good times down, well done.
You've got some boost going on there. It must be handling it alright?
George

[Turboblew2]

lower your short & 330 times... you already have 9s based on MPH.
Should not be a problem to hand clutch into a 1.6 60' Magazine riders defacto 60' is a 1.7.
Tilt the bike right and soak the plates with sump oil in the burnout box. Shallow stage

[Lorcan]

A better 60' would put you in the 9s, for sure. I ran mid 1.5s on my lowered 60" bike, but admittedly I've always liked wheelies!

[georgew4714]

Still out there chasing 9s ?

Just read through this post , lot of helpful info for us noobies.